Levantamento do banco de sementes de plantas espontâneas em área de pastagem no município de Rio Bonito do Iguaçu – PR

Abstract

The present work consists of a survey of the weed seed bank in a pasture of the municipality of Rio Bonito do Iguaçu - PR. The soil seed bank is the number of viable seeds present in the soil matrix and the managements used in the production systems significantly influence its composition. This type of survey has great importance in the knowledge about the community and the biology of the species present. For its determination, the most used procedure consists of counting the seeds readily germinable from soil samples collected from the place of interest. This soil is dried, cleaned and distributed in trays in equal amounts, to be watered daily, giving conditions for the seeds to germinate. During the 56 days of soil incubation, results were obtained, and it was possible to qualify and measure the species that presented emergence. The composition of the seed bank had 190 seedlings, presenting a certain diversity of weed species, with the presence of 9 plant genus from 9 botanical families. Among the emergencies, some species were superior in relation to their occurrence compared to the others, such as: broad buttonweed (Spermacoce latifolia), pillpod sandmat (Chamaesyce hirta), amaranth (Amaranthus hybridus) and Sida glaziovii. These showed the highest values in the number of readily germinable seeds per m², density, relative density, frequency, relative frequency, abundance, relative abundance, importance value index and relative importance value index. By separating all emerging species into classes, it was possible to perceive that most are dicotyledons, representing a total of 68.42%. It is noticed that most species are common to be found in crop systems, this may be a result of different ways of seed dispersal. Due to the large production of seeds and their easy dissemination, the species that showed the highest emergence in the seed bank are the ones that most need attention in relation to their management in the field.